Handbook of Solvents - George Wypych - ChemTech - Ventech!

2.3 Basic physical and chemical properties 45
Viscosity, cP
8
7
6
5
4
3
2
1
alcohols
aromatic CH
esters
ketones
0
50 100 150 200 250 300
Boiling point, o C
Figure 2.3.2. Effect of boiling point on solvent
viscosity.
Specific heat, cal k -1 mol -1
100
80
60
40
20
alcohols
aromatic CH
esters
ketones
0
50 100 150 200 250
Boiling point, o C
Figure 2.3.4. Specific heat of solvents vs. their boiling
point.
Evaporation rate
0
50 100 150 200 250
than other three groups of solvents and for the same reason. Viscosity and evaporation rate
of aromatic hydrocarbons, esters, and ketones follow single relationship for all three groups
of solvents, meaning that the boiling point has strong influence on these two properties.
There are individual points on this set of graphs which do not fall close to the fitted curves.
These discrepancies illustrate that chemical interactions influence viscosity and evaporation
rate. However, for most members of the four groups of solvents, properties correlate
most strongly with boiling point.
All linear relationships in Figure 2.3.4 indicate that specific heat is strongly related to
the boiling point which is in agreement with the fact that boiling point is influenced by molecular
weight. However, there are substantial differences in the relationships between dif-
12
10
8
6
4
2
Boiling point, o C
alcohols
aromatic CH
esters
ketones
Figure 2.3.3. Effect of boiling point on solvent
evaporation rate (relative to butyl acetate = 1).
Flash point, o C
200
150
100
50
0
alcohols
aromatic CH
esters
ketones
-50
50 100 150 200 250 300
Boiling point, o C
Figure 2.3.5. Flash point of solvents vs. their boiling
point.